MCCONNELL CALLS FOR 14TH AMENDMENT HEARING…. For about 142 years now, the American political mainstream hasn’t been especially troubled by the first 28 words of the 14th Amendment: “All persons born or naturalized in the United States and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside.”

But the drive to scrap this constitutional right — in response to anti-immigrant hysteria among conservatives — is spreading quickly. What was up until recently a fringe right-wing fantasy is now being taken seriously at the highest levels of Republican politics.

Senate Minority Leader Mitch McConnell (R-Ky.) told The Hill on Monday that Congress “ought to take a look at” changing the 14th Amendment, which gives the children of illegal immigrants a right to U.S. citizenship.

McConnell’s statement signals growing support within the GOP for the controversial idea, which has also recently been touted by Senate Minority Whip Jon Kyl (R-Ariz.) and Sen. Lindsey Graham (R-S.C.).

In an interview, McConnell said the 14th Amendment provision should be reconsidered in light of the country’s immigration problem.

Unlike Lindsey Graham, McConnell didn’t explicitly call for a constitutional amendment to repeal part of the 14th, but described the matter as “something that we clearly need to look at.”

He added, “Regardless of how you feel about the various aspects of immigration reform, I don’t think anybody thinks that’s something they’re comfortable with.”

I have no idea what this means. Everyone is uncomfortable with birthright citizenship? The law of the land for the last 142 years, written into constitutional stone, has gone from being universally accepted to universally reviled … because Mitch McConnell says so?

Chances are, the Democratic majority won’t take these calls for hearings especially seriously, but if there’s a Republican majority in the next Congress, it seems quite likely that questioning the 14th Amendment will be fairly high on the GOP to-do list.

If I had to guess, I’d say this is political posturing taken to an extreme level. In times of economic anxiety, the right historically exploits public fears and attacks immigrants, making this constitutional push offensive, but at least somewhat consistent with conservative history.

But to dismiss this effort to appeal to right-wing voters as routine and unimportant would be a mistake. We’re talking about a major political party, perhaps even a soon-to-be congressional majority, rejecting the tenets of the 14th Amendment for crying out loud. And not just some obscure back-benchers or powerless state legislators — this is becoming the GOP mainstream position thanks to the support of the most powerful figures in Republican politics.

Just when it seemed as if the Republican Party couldn’t possibly become more irresponsible, more detached from a sensible mainstream, more beholden to demagogues and fanatics, the GOP kicks things up a notch. Whether they’re rewarded for their extremism will be clear in 13 weeks.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.